// Copyright (c) 2021 Dmitry Meduho
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// Notwithstanding the foregoing, you may not use, copy, modify, merge, publish,
// distribute, sublicense, create a derivative work, and/or sell copies of the
// Software in any work that is designed, intended, or marketed for pedagogical or
// instructional purposes related to programming, coding, application development,
// or information technology.  Permission for such use, copying, modification,
// merger, publication, distribution, sublicensing, creation of derivative works,
// or sale is expressly withheld.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

import AppKit

// MARK: - Protocols

public protocol FileService {
    func getDirectoryContent(from url: URL, imageFormat: [ImageFormatType]) throws -> [URL]
    func getFilesize(_ url: URL) throws -> UInt64
}

// MARK: - Class

public final class FileServiceImpl: FileService {
    private let imageCore: ImageCore
    private let fileCore: FileCore
    
    // MARK: - Initializer
    
    public init(
        imageCore: ImageCore,
        fileCore: FileCore
    ) {
        self.imageCore = imageCore
        self.fileCore = fileCore
    }
    
    // MARK: - Public

    public func getDirectoryContent(from url: URL, imageFormat: [ImageFormatType]) throws -> [URL] {
        let content = try fileCore.getDirectoryContent(from: url)
        let images = validateImages(content, imageFormat: imageFormat)
        return images
    }
    
    public func getFilesize(_ url: URL) throws -> UInt64 {
        return try fileCore.getFilesize(url)
    }
    
    // MARK: - Private
    
    private func validateImages(_ urls: [URL], imageFormat: [ImageFormatType]) -> [URL] {
        var preparedUrls: [URL] = []

        for url in urls where imageCore.validateImage(url, imageFormat: imageFormat) {
            preparedUrls.append(url)
        }

        return preparedUrls
    }
}
